Voltages small

Mg Mg(OH)2 X 0 0 Large rise in cell voltage, small effect on current efficiency. 

Direct Current. Direct-current (DC) motors normally come with either an internal or external rectification system matched to the motor duty. The rectification of alternating current to direct current by solid-state electronics allows the control of motor speed by adjusting the applied voltage. Small DC motors, less than 5 hp (3700 W), are typically permanent magnet designs larger motors are shunt wound. 

Most of the advantages of MCB technology can be used to make small anode-grounded metal-ceramic X-ray tubes as well. These could be water- or air-cooled and reach power ranges up to 1 kW at voltages up to lOOkV. 

Figure 1. shows the measured phase differenee derived using equation (6). A close match between the three sets of data points can be seen. Small jumps in the phase delay at 5tt, 3tt and most noticeably at tt are the result of the mathematical analysis used. As the cell is rotated such that tlie optical axis of the crystal structure runs parallel to the angle of polarisation, the cell acts as a phase-only modulator, and the voltage induced refractive index change no longer provides rotation of polarisation. This is desirable as ultimately the device is to be introduced to an interferometer, and any differing polarisations induced in the beams of such a device results in lower intensity modulation. 

In fact, some care is needed with regard to this type of concentration cell, since the assumption implicit in the derivation of A2.4.126 that the potential in the solution is constant between the two electrodes, caimot be entirely correct. At the phase boundary between the two solutions, which is here a semi-pemieable membrane pemiitting the passage of water molecules but not ions between the two solutions, there will be a potential jump. This so-called liquid-junction potential will increase or decrease the measured EMF of the cell depending on its sign. Potential jumps at liquid-liquid junctions are in general rather small compared to nomial cell voltages, and can be minimized fiirther by suitable experimental modifications to the cell. 

Threshold voltage. Batteries can only supply low voltages, so for portable appliances the switching voltage or tlireshold voltage must be sufficiently small. 

A true baseline output from an ion detector is electrically noisy and, if recorded as such, the noise would appear as a great many small (unwanted) peaks. By creating an artificial baseline at a voltage just above the noise, the small peaks are eliminated and only the desired signal is recorded. It is important not to set the artificial baseline voltage too high, since this would eliminate too much of the required peak. 

A successful modification to the technique involves delayed pulsed-field extraction which allows discrimination between zero and near-zero kinetic energy electrons. About 1 ps after the laser pulse has produced photoelectrons, a small voltage pulse is applied. This has the effect of amplifying the differences in fhe velocities of fhe phofoelecfrons and allows easy discrimination befween fhem as a resulf of fhe differenf times of arrival af fhe defector. In fhis way only fhe elections which originally had zero kinetic energy following ionization can be counted to give fhe ZEKE-PE specfmm. 

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